When ensuring articles for sale against burglary it is important that the markers are easy to mount on the articles for sale and only can be removed by an authorized person such as a shop assistant. The available markes are encumbered with the problem that the first member for instance shaped as a solid drawing pin sometimes can be pulled out of the lock merely by subjecting the head of the "drawing pin" to an upward pull, cf. for instance U.S. Pat. No. 3,858,280.